Earth Science, Glencoe/McGraw-Hill, 1999
Authors: Ralph Feather and Susan Snyder
Earth Science Grade 9 (ages 14-15)
Chapter 24: Stars and Galaxies
Lesson: Evolution of Stars
Part 2 – Unpack Learning Goals
Learning Goal: ESS3 (9-11)–8
Students demonstrate an understanding of the life cycle of stars by …
8.a Relating the process of star formation to the size of the star and including the interaction of the force of gravity, fusion, and energy release in the development of the star identifying and describing the characteristics common to most stars in the universe.
What does this standard mean?
Stars are formed by the fusion of hydrogen into helium in their cores
Stars are classified on the Hertzsprung-Russell (H-R) Diagram by the relationship of their temperature and magnitude
Heat from fusion causes pressure and balances the attraction due to gravity to maintain a star’s formation
Stars evolve and change as the balance between the pressure and gravity changes
Stars begin as a large cloud of dust called a nebula
When the balance between pressure and gravity is lost the star core begins to contract creating giants, white dwarfs, and supergiants
When stars die their cores collapse creating a supernova explosion
What prior knowledge do students need to know to understand the standard?
Properties of elements (hydrogen, helium)
Thermal and hydrostatic equilibrium
Process of Fusion= lighter elements combining to create larger ones
Apparent magnitude = brightness
Mass can be converted into energy (E=mc2)
Properties of gravity
·Color spectrum in relation to temperature
What misconceptions might students have around the topics contained in the standard?
Think red stars are the hottest (red hot, blue cold)
Think massive stars may live longer then less massive ones
Think stars are fueled by the burning of gas
Think the brightness of a star depends on its distance
Part 3 – Analyze selected features of the material
Category III – Engaging Students with Relevant Phenomena
Criterion III A – Providing a Variety of Phenomena
Sightings of the Criteria:
The H-R diagram is a graph that shows the relationship of a stars temperature and its absolute magnitude. (pg 684).
Figure 24-10: H-R Diagram showing the types of stars and their location on the diagram relevant to their magnitude, size, color, and temperature
The process of fusion causes stars to shine and produce large amounts of heat
Figure 24-12: llustrates the step by step process of two hydrogen atoms fusing together to produce four helium atoms
Stars start out as a cloud of dust and gas called a nebula and through contraction and gravitation form into stars (pg 686)
As stars evolve they create main sequence stars, giants, supergiants, and white dwarfs (687-688).
When stars die they can cause major explosions called supernovas or create black holes (pg 688)
Figure 24-13: Shows lives of stars and the different paths they take pending on their masses
Figure 24-14: shows a picture of a supernova explosion taken by the Hubble Space Telescope
Indicators of meeting the criterion:
Phenomena are usefuluseful in making the key ideas real.
Phenomena are explicitlylinked to the relevant key ideas
The phenomena present in this chapter section were observed and presented mostly through text and pictures. The chapter did meet some of the indicators for 1 and 2. The phenomena presented were very general and could have been more specific in linking all of the ideas together. Therefore the criteria met was Satisfactory.
Criterion III B – Providing Vivid Experiences
Sightings of the Criteria:
Figure 24-10: H-R Diagram showing the types of stars and their location on the diagram relevant to their magnitude, size, color, and temperature
Figure 24-13: Shows lives of stars and the different paths they take pending on their masses
Explanation of the process of star evolution and the cause of each type of star in the progression (pg 686-688)
Skill Builder: sequencing stars in the order that they evolve in (pg 690)
Developing skills: Questions 21-22. Using a table displaying types of stars, their absolute and apparent magnitudes, and distances students are to list the stars from brightest to faintest.
Developing skills:Question 23: Students are to create a concept map that shows the evolution of a main sequence star similar to that of the sun
Indicators of meeting the Criterion:
1. Each firsthand experience is efficient (when compared to other firsthand experiences) and, if several firsthand experiences target the same idea, the set of firsthand experiences is efficient. (The efficiency of an experience equals the cost of the experience [in time and money] in relation to its value.)
2. The experiences that are not firsthand (e.g., text, pictures, video) provide students with a vicarious sense of the phenomena. (Please note that if the material provides only firsthand experiences, this indicator is not applicable.)
3. The set of firsthand and vicarious experiences is sufficient.
This chapter does not include many firsthand experiences other than reading tables and concept mapping. It does however, include a substantial amount of experiences that are not firsthand but provide a vicarious sense of the phenomena. Therefore the criteria met was Satisfactory.
Category IV – Developing and Using Scientific Ideas
Criterion IV B – Representing Ideas Effectively
Sightings of Criteria:
Figure 24-10: H-R Diagram showing the types of stars and their location on the diagram relevant to their magnitude, size, color, and temperature
Figure 24-11: Shows the relative size range of stars in comparison to one another
Figure 24-12: Illustrates the step by step process of two hydrogen atoms fusing together to produce four helium atoms
Figure 24-13: Shows lives of stars and the different paths they take pending on their masses
Explains the sizes of certain stars (giants, supergiants) by comparing them to the size of our sun (687)
Shows size of a white dwarf by comparing it to the size of the earth (pg 688)
Indicators of meeting the Criterion:
Representation is accurate (or, if not accurate, then students are asked to critique the representation).
Representation is likely to be comprehensible to students.
Representation is explicitly linked to the real thing.
The diagrams and pictures in the chapter were easy to comprehend and gave a good representation of the material discussed in the chapter. The chapter also used analogies with relative material to emphasis certain ideas. However, I think that there could have been more of a variety of representations then the ones provided in the chapter. The criteria met was Excellent.
Part 4 – Applying Evaluation to Teaching
The chapter starts with discussing H-R diagrams and where stars are located on it. Then it goes into the evolution of stars and the different features of each star in the process. When teaching the topic I would begin talking about the process of fusion and how it allows stars to shine. I would reference the figure in the textbook that shows the fusion process in stars. Once students understand how fusion works the next step would be teaching them the process that stars go through in the course of there lifetime. I would explain each step in the process discussing how each type of star forms and why. The figure that illustrates this process would also be used at this time.
After, I would go back to the beginning of the chapter to introduce the H-R diagram. By this time the students will know the characteristics of each type of star and it will be easier for them to understand diagram along with where each star is located on it and why. I think the H-R diagram reference in the text is a good example but I would have to add more. One activity I would add is giving students a table that lists the names of different stars along with their temperatures and magnitudes. The students would have to plot the stars on their own H-R diagram. After plotting them the students would then have to identify what type of star each one was by looking that the diagram they plotted. During this type of lesson I would also try to find a video that explains the star evolution process and can show real examples of each type of star. I think that the video would be more relevant and interesting then the limited pictures that are found in the textbook. The students would use the text in conjunction the lesson by reading the pages of the chapter ahead of time and referencing the figures that are relevant to the specific topics being covered at the time.
Earth Science, Glencoe/McGraw-Hill, 1999
Authors: Ralph Feather and Susan Snyder
Earth Science Grade 9 (ages 14-15)
Chapter 24: Stars and Galaxies
Lesson: Evolution of Stars
Part 2 – Unpack Learning Goals
Learning Goal: ESS3 (9-11)–8
Students demonstrate an understanding of the life cycle of stars by …
8.a Relating the process of star formation to the size of the star and including the interaction of the force of gravity, fusion, and energy release in the development of the star identifying and describing the characteristics common to most stars in the universe.
What does this standard mean?
What prior knowledge do students need to know to understand the standard?
What misconceptions might students have around the topics contained in the standard?
Part 3 – Analyze selected features of the material
Category III – Engaging Students with Relevant Phenomena
Sightings of the Criteria:
Indicators of meeting the criterion:
The phenomena present in this chapter section were observed and presented mostly through text and pictures. The chapter did meet some of the indicators for 1 and 2. The phenomena presented were very general and could have been more specific in linking all of the ideas together. Therefore the criteria met was Satisfactory.
Sightings of the Criteria:
Indicators of meeting the Criterion:
1. Each firsthand experience is efficient (when compared to other firsthand experiences) and, if several firsthand experiences target the same idea, the set of firsthand experiences is efficient. (The efficiency of an experience equals the cost of the experience [in time and money] in relation to its value.)
2. The experiences that are not firsthand (e.g., text, pictures, video) provide students with a vicarious sense of the phenomena. (Please note that if the material provides only firsthand experiences, this indicator is not applicable.)
3. The set of firsthand and vicarious experiences is sufficient.
This chapter does not include many firsthand experiences other than reading tables and concept mapping. It does however, include a substantial amount of experiences that are not firsthand but provide a vicarious sense of the phenomena. Therefore the criteria met was Satisfactory.
Category IV – Developing and Using Scientific Ideas
Sightings of Criteria:
Indicators of meeting the Criterion:
The diagrams and pictures in the chapter were easy to comprehend and gave a good representation of the material discussed in the chapter. The chapter also used analogies with relative material to emphasis certain ideas. However, I think that there could have been more of a variety of representations then the ones provided in the chapter. The criteria met was Excellent.
Part 4 – Applying Evaluation to Teaching
The chapter starts with discussing H-R diagrams and where stars are located on it. Then it goes into the evolution of stars and the different features of each star in the process. When teaching the topic I would begin talking about the process of fusion and how it allows stars to shine. I would reference the figure in the textbook that shows the fusion process in stars. Once students understand how fusion works the next step would be teaching them the process that stars go through in the course of there lifetime. I would explain each step in the process discussing how each type of star forms and why. The figure that illustrates this process would also be used at this time.
After, I would go back to the beginning of the chapter to introduce the H-R diagram. By this time the students will know the characteristics of each type of star and it will be easier for them to understand diagram along with where each star is located on it and why. I think the H-R diagram reference in the text is a good example but I would have to add more. One activity I would add is giving students a table that lists the names of different stars along with their temperatures and magnitudes. The students would have to plot the stars on their own H-R diagram. After plotting them the students would then have to identify what type of star each one was by looking that the diagram they plotted. During this type of lesson I would also try to find a video that explains the star evolution process and can show real examples of each type of star. I think that the video would be more relevant and interesting then the limited pictures that are found in the textbook. The students would use the text in conjunction the lesson by reading the pages of the chapter ahead of time and referencing the figures that are relevant to the specific topics being covered at the time.